Wireless receiving arrangement with frame antenna



March 5, 1940. K. H. MEIER 2,192,321

WIRELESS RECEIVING ARRANGEMENT WITH FRAME ANTENNA Filed April 5. 1938 Inventor:

Kari Hmnnch N w IYNVEN Fora Patented Mar. 5, 1940 WIRELESS RECEIVING ARRANGEMENT WITH FRAME ANTENNA:

Karl Heinrich Meier, Zurich, Switzerland, assignor 'to 'EmiL Huber, liiilchberg, Zurich,

Switzerland Application April s, 1938, Serial No. 200,219 In Switzerland April 16,1937

2 Claims. (oi. 250-20) The present invention relates to a wireless broadcast receiving arrangement, in which a frame antenna. is used as the effective receiving part. A receiving arrangement working with a frame antenna does not exhibit the susceptibility to disturbance of an arrangement working with an elevated antenna, however, it is necessary to locate the receiving frame, analogously to the elevated antenna, outside the local disturbance field, if its advantages are to be fully realised. Whilst it is possible without difliculty to rotate the receiving frame, by electrical or mechanical means, from the service position into the desired receiving direction, various difliculties arise in decoupling the receiving frame from neighbouring carriers of disturbing potential. Moreover the directional property of the frame is to some extent adversely affected by the fact that a part of the Winding of the frame operates simultaneously as a rod antenna. the receiving frame therefore has the result that both electromagnetic radiation and electrostatic fields act on the receiving apparatus.

A further source of disturbance is constituted by the fact that transmitters of disturbance operating in the neighbourhood of the receiver, such as small motors, household appliances and the like, radiate disturbing electromagnetic waves, which are propagated along metallic conductors with markedly smaller lossesthan when they are propagated wirelessly; thus disturbing radiations arising from the neighbouring field of disturbance are propagated along the coupling cable between the antenna and the receiver and so come to affect the receiver;

According to'this invention,these objections are overcome by arranging the winding forming the receiving frame, together with the coupling conductor between the receiving frame and the input circuit of the receiver and together with at least the input stage of the receiver, wholly within electrostatic screening means, the screening around the antenna being interrupted at one point but being effectively continuous electrostatically, and by arranging that these screening means have the common datum potential of the receiving apparatus as a whole, for example,

' statically by means of a tubular sheath which is interrupted at one point, so that this screening sheath exhibits no short-circuit for the frame,

This combined operation of i the ends of the tubular sheath being overlapped and, separated by dielectric so as to maintain the electrostatic screening. I v

It has already been proposed to screen various parts of receiving apparatus such as a frame antenna and its coupling conductor and the input Wireless broadcast receiving installation of the 15 present invention, and g Fig. 2 shows, to a larger scale, a modification of a detail. I

A rotatable antenna head 5, which is provided witha metallic coating and carries the frame antenna 6, is mounted on the mast i by means of ball-bearings 3, 4. The rotatable head is adjustable in its bearings about the vertical axis with the aid of a worm wheel l, a worm t, a worm wheel'ii and a Worm M3 by means of an electric motor which is not shown. The frame antenna 6 has an outer metal tube l2 within which is disposed the frame winding l l. The winding of the frame antenna may be constructed in a simple manner by drawing the wires together intothe tube l2 and connecting them together in series by means of the soldering block. it. The beginning l4 and the and E5 of the frame winding are each connected with one end of the'primary coil IS of the antenna transformer ii. The secondary winding 18 of the transformer ii is connected with the primary coil 2] of the transformer 22 of the input circuit of the receiver by means of.

leads I9, 26. The frame Winding ll of the an tenna 6 is coupled aperiodically with the input circuit ofjthereceiver. The secondary coil 23 of the transformer 22 is adjustable to the transmitter to be received by means of the condenser 26. The amplification of the received waves 26 of the receiver which is not further illustrated. The coupling conductors it, it between the antennatransformer Ill and the input circuit of the receiver are screened electrostatically by the screening means 21. This screening means 21 is connected conductively at point 223 with takes place at first by the first amplifier tube the casing 2 of the receiver and on the other hand by means of the bridge 29 with the metal coating of the rotatable antenna head 5, The. metal tube I2 of the frame antenna is conductively connected by means of a bridge tll with the rotatable head 5. In order that this metal tube l2 may not be a short circuit; turn for the frame, the ends of this'tube, are insulated from the rotatable antenna head 5 by means of sleeves 3| of dielectric material, and in orderthat the electrostatic screening may be effectively continuous, the ends of the tube are arranged; to overlap .the metallic coating on j the antenna head 5. l

Instead of being as shown in Fig. 1, both ends of the tube l2 may be directly connected COD? ductively with the rotatable head at their points of entry into the rotatable head. The metaltube of the antenna must then be split at some point so that it forms no .short circuitturn'for the frame. In this case it is advantageous to split the tube at the upper midpoint of the frame. In

the interruption.

1. A wireless receiving arrangement compris ing a radio receiver having an initial stage and an input circuit thereinto, a frame antenna and coupling conductors between said frame antenna and said input circuit; and electrostatic screening means comprising a-metallic shield enclosing,

said antenna, said coupling conductors,-and at least said initial stage of said radio receiver, said I metallic shield around the antenna being interrupted at one point, but eifeotively continuous electrostatically, and connected to thecommon potential point of the receiving arrangement as a whole whereby the wireless receiving arrangement is completely screened electrostatically.

2. A wireless receiving arrangement according to claim 1 wherein said metallic shield around the antenna is of tubular form with the two adjacent ends at the point of interruption being spaced in overlapping relation with dielectric material separating said ends, whereby the electrostatic screening is substantially unafiected DY 

